Why Do 3D Wooden Puzzles Sometimes Fit Too Tight or Too Loose?

Have you ever noticed that some wooden 3D puzzles fit together tightly while others seem a bit loose? There are two main reasons behind this phenomenon.

What causes the variation in tightness?

Firstly, the thickness of the wooden boards can vary due to tolerance issues. Wooden boards, limited by the manufacturing process, typically have a thickness tolerance fluctuation of 5% to 10%. Additionally, the absorption of moisture by the wood and its sensitivity to humidity can also lead to thickness changes. If the board is thicker than the design, the puzzle pieces will fit tightly; if it is thinner, the pieces will fit loosely.

Secondly, the precision of laser cutting plays a significant role. 3D puzzles are usually crafted using laser cutting to obtain the parts. The laser burns the wood, leaving cutting gaps on the board due to the width of the laser beam. The typical width of a laser beam ranges from 0.2mm to 0.3mm, requiring precise focusing on the cutting plane. If the laser cutting machine is not accurately focused or if the wood thickness varies, leading to inaccurate focusing, the cutting lines may become thicker, resulting in excess material being cut off and potentially causing a loose fit.

How can this issue be resolved?

To address this issue, designers can strive to avoid excessively loose or tight fits during the puzzle assembly process. Additionally, strengthening quality inspection and control is crucial. By measuring and selecting the required wood thickness, adjusting process parameters based on wood tolerance, and conducting visual inspections and measurements post-cutting, product quality can be ensured.